1. Field of the Invention
The present invention relates to a rear suspension for a three-wheeled car, and more particularly, to a rear suspension for a three-wheeled car, which comprises two front wheels and one rear wheel, in which the toe angle camber angle of the rear wheel is automatically adjusted by the direction the car is turning so that the stability is enhanced when the car is turning.
2. Description of Related Art
Currently, the efforts to improve the fuel efficiency of a car are being made continuously and globally. As a part of making such efforts, the studies on improving the performance of a power-train and on reducing the weight of a car continue to be conducted.
In furtherance of this idea, a three-wheeled car has been newly developed as a more environment-friendly transportation means and as a lighter vehicle.
As mentioned above, a three-wheeled car developed with the environment-friendly and the lighter-weight concept has a structure of either one front wheel with two rear wheels triangle structure or one rear wheel with two front wheels inverted triangle structure. Compared to a four-wheeled vehicle, a three-wheeled car has the advantage of being lighter and more fuel-efficient, and yet, it has the disadvantage of having less stability while on the road.
Of the above-mentioned two types of three-wheeled cars, a swing-arm type was used mainly for a traditional rear suspension applied to a three-wheeled car with two front wheels and one rear wheel which was usually applied in the rear wheel of a motorcycle and only allowed the up-and-down motion.
In reference to FIG. 1, the traditional suspension structure of a three-wheeled car with two front wheels and one rear wheel is designed so that a H-shaped arm is connected to the rear end of the car frame through a hinge pin so that it can perform hinge movements up-and-down pivot movements and the impact be buffered by the bump and rebound movement of a shock absorber.
In other words, the rear end of the swing arm is combined with the axis of rotation of the rear wheel and the front end of the swing arm is combined with the car body, but it is composed so that it can perform up-and-down pivot movements as the ground surface is uneven.
Compared with a four-wheeled car, a three-wheeled car with one rear wheel has half the cornering force, supposing they are both equipped with identical tires. Therefore, when turning an identical corner, a three-wheeled car has a greater chance of a spin-out because its lateral force the resilience against the force applied laterally as a car turns a corner in the rear wheel is smaller than that in the rear wheels of a four-wheeled car. In other words, there was the problem of diminished stability when a three-wheeled car is turning.
Also, the swing-arm type suspension structure had a tendency for a toe-out when the lateral force is applied due to the compliance effect the effect as though the handle is being steered when the external forces change the forms of rubber bushes for suspension and hence change the alignment.
Thus, the stability of a car when it is turning is significantly reduced if it uses a swing-arm type suspension such as the one described above due to the centrifugal force and the lateral force which induce the over-steer moment.
Hence, there is the problem of a rear wheel breaking away from the right track and the stability of a car decreasing when a car is on the road.
The information disclosed in this Background of the Invention section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.